Republicans in Congress have joined the White House in asking questions about the extent to which a Democratic Party consultant may have worked with Ukrainian officials to hurt then-candidate Donald Trump's presidential bid last year.

Senate Judiciary Committee Chairman Chuck Grassley wrote a letter earlier this week to the Justice Department asking whether the Democratic National Committee broke the law. Grassley, R-Iowa, specifically asked if the DOJ was investigating Alexandra Chalupa, a Ukrainian-American DNC consultant who allegedly had meetings at the Ukrainian Embassy in Washington, D.C., to discuss incriminating information about Trump campaign officials.

President Trump, trying furiously to tamp down the controversy over alleged Russian coordination with his associates, has questioned why the same scrutiny is not being applied to the Democrats' alleged Ukraine connection.

In a Tuesday tweet, he complained about the lack of an investigation into Ukraine efforts to "sabotage" his campaign.